Pinch Test Research Articles

The effectiveness and safety of topical PhotoActif phosphatidylcholine‐based anti‐cellulite gel and LED (red and near‐infrared) light on Grade II–III thigh cellulite: A randomized, double‐blinded study

Background: Cellulite of the upper lateral and posterior thighs and lower buttocks represents a common, physiological and unwanted condition whose etiologies and effective management are subjects of continued debate. Objective: The purpose of this controlled, double‐blinded study is to evaluate the efficacy and safety of a novel phosphatidylcholine‐based, cosmeceutical anti‐cellulite gel combined with a light‐emitting diode (LED) array at the wavelengths of red (660 nm) and near‐infrared (950 nm), designed to counter the possible mechanisms that purportedly accentuate the presence of thigh cellulite. Methods: Nine healthy female volunteers with Grade II–III thigh cellulite were randomly treated twice daily with an active gel on one thigh and a placebo gel on the control thigh for 3 months. Twice weekly, each thigh was exposed for a 15‐minute treatment with LED light for a total of 24 treatments. At 0, 6, and 12 weeks of the study the following clinical determinants were obtained: standardized digital photography, height and weight measurements, standardized thigh circumference tape measurements, pinch testing, body mass index (kg/m2), body fat analysis (Futrex‐5500/XL near‐infrared analyzer), and digital high‐resolution ultrasound imaging of the dermal–adiposal border. In selected patients, full‐thickness biopsies of the placebo and active‐treated sites were obtained. At 18 months, repeat standardized digital photography, height and weight measurements, and body mass index measurements were obtained. Results: At the end of 3 months, eight of nine thighs treated with the phosphatidylcholine‐based, anti‐cellulite gel and LED treatments were downgraded to a lower cellulite grade by clinical examination, digital photography, and pinch test assessment. Digital ultrasound at the dermal‐adiposal interface demonstrated not only a statistically significant reduction of immediate hypodermal depth, but also less echo‐like intrusions into the dermal layer. Three of six biopsies from thighs treated for 3 months with the active gel and LED treatments demonstrated less intrusion of subcutaneous fat into the papillary and reticular dermis. In nine placebo and LED‐treated thighs and one of the actively treated thighs, minimal clinical changes were observed or measured by the clinical determinants throughout the 3‐month study. At the month‐18 evaluation period for the eight responsive thighs, five thighs reverted back to their original cellulite grading, while three thighs continued to maintain their improved status. Patients experienced minimal and transient side effects that included puritus, erythema and swelling. Conclusions: The results of this small but well‐documented, randomized, double‐blinded study affirms that eight of nine thighs with Grade II–III cellulite responded positively to a novel, combined 3‐month treatment program of a phosphatidylcholine‐based, anti‐cellulite gel and LED exposure, as determined by the clinical determinants obtained. Patients experienced minimal and transient side effects. At the month‐18 evaluation period (15 months after treatment), five responsive thighs reverted back to their original cellulite grading, indicating a need for maintenance treatment. Future studies are needed to verify these tentative positive observations.

A new test for demonstrating the action of flexor digitorum superficialis (FDS) tendon

The available tests for demonstrating the action of flexor digitorum superficialis (FDS) can be used on one finger at a time. A new test is proposed which can test all the four FDS tendons simultaneously. It was administered along with other available tests on 100 uninjured hands of 50 volunteers and on seven clinical cases with FDS injury. It correlated fully (100%) with the standard test on middle and ring fingers and with the pulp-to-pulp forced pinch test with the thumb on index fingers. It was more accurate than the standard test in detecting the presence of FDS action on the little finger. It was found to be in strong agreement with the modified standard test on little finger with a kappa coefficient of 0.98. It correlated fully for the absence of FDS tendon action in seven operatively proved cases. The present test is a new test which is faster and more versatile than the available tests.

A Randomized, Controlled Trial of Distal Radius Fractures With Metaphyseal Displacement but Without Joint Incongruity: Closed Reduction and Casting Versus Closed Reduction, Spanning External Fixation, and Optional Percutaneous K-wires

To compare closed reduction and casting with closed reduction and external fixation with optional K-wire fixation for distal radius fractures with metaphyseal displacement but without joint incongruity. Prospective study. Multicenter study at 3 University teaching hospitals. A total of 113 skeletally mature patients with distal radius fractures with metaphyseal displacement, but without joint incongruity, were randomized to receive 1 of 2 standardized treatment protocols. Patients were evaluated at 6 weeks, 6 months, 1 year, and 2 years. Closed reduction and casting (n = 59) or closed reduction and external fixation (n = 54). Upper extremity function was measured using upper extremity MFA domain scores, overall Jebsen Taylor scores, and pinch and grip strength tests. Global function and pain were measured using the SF-36. Radiographic evaluation and range of motion were documented. Upper extremity MFA scores, Jebsen Taylor scores, SF-36 bodily pain scores, and grip strength improved significantly during the first year for all patients. By 2 years, mean Jebsen Taylor scores and SF 36 bodily pain scores for patients in both groups were similar to scores for normal age- and gender-matched population controls. At all points, there was a trend for better function in the external fixation; however, this did not reach statistical significance. There was a trend for better length and palmar tilt restoration with external fixation. For distal radius fractures with metaphyseal displacement but with a congruous joint, there exists a trend for better functional, clinical, and radiographic outcomes when treated by immediate external fixation and optional K-wire fixation.

Rescue and regeneration of injured peripheral nerve axons by intrathecal insulin

Insulin peptide, acting through tyrosine kinase receptor pathways, contributes to nerve development or repair. In this work, we examined the direction, impact and repertoire of insulin signaling in vivo during peripheral nerve regeneration in rats. First, we demonstrated that insulin receptor is expressed on lumbar dorsal root ganglia neuronal perikarya using immunohistochemistry. Immunoblots and polymerase chain reactions confirmed the presence of both α and β insulin receptor subunits in dorsal root ganglia. In vivo and in vitro assessment of dorsal root ganglion neurons showed preferential localization of insulin receptor to perikaryal sites. In vivo, intrathecal delivery of fluorescein isothiocyanate-labeled insulin identified localization around dorsal root ganglia neurons. The direction and impact of potential insulin signaling was evaluated by concurrently delivering insulin or carrier over a 2 week period using mini-osmotic pumps, either intrathecally, near nerve, or with both deliveries, following a selective sural nerve crush injury. Only intrathecal insulin increased the number and maturity of regenerating sensory sural nerve axons distal to the crush site. As well, only intrathecal insulin rescued retrograde loss of sural axons after crush. In a separate experiment, insulin also rescued retrograde loss and atrophy of deep peroneal, largely motor, axons post-injury. Intrathecal insulin increased the expression of calcitonin-gene-related peptide in regenerating sprouts, increased the number of visualized regenerating fiber clusters, and reduced downregulation of calcitonin-gene-related peptide in dorsal root ganglia neurons. Insulin delivered intrathecally does not appear to influence expression of insulin-like growth factor-1 at dorsal root ganglion neurons or near peripheral nerve injury, but was associated with upregulation of insulin receptor α subunit in dorsal root ganglia. Intrathecal insulin delivery was associated with greater recovery of thermal sensation and longer distances to stimulus response with the pinch test following sural nerve crush. Insulin signaling at neuron perikarya can drive distal sensory axon regrowth, rescue retrograde alterations of axons and alter axon peptide expression. Moreover, such actions are associated with upregulation of its own receptor.

CD26 modulates nociception in mice via its dipeptidyl-peptidase IV activity

Background CD26 is a multifunctional cell surface glycoprotein expressed by T and B cells. It exhibits a dipeptidyl-peptidase activity (DPP-IV) that cleaves the penultimate proline from the N-terminus of polypeptides, thereby regulating their activity and concentration. Methods Using CD26−/− mice resulting from targeted inactivation of the gene, we examined the consequences of a DPP-IV defect on behavioural response to nociceptive stimuli and concentration of the pain modulator peptides substance P (SP) and endomorphin 2, two DPP-IV substrates. Results CD26 inactivation induced a three-fold decrease in circulating endopeptidase activity while that found in brain extracts was normal, albeit very weak. CD26−/− mice had high SP concentrations in plasma (3.4 ± 1 pg/ml versus 1.5 ± 0.3 pg/ml, P < 10 −3) but not in brain extracts (35 ± 12 pg/ml versus 32 ± 9 pg/ml, P > 0.05). Endomorphin-2 levels in the two groups were in the same range for plasma and brain extracts. CD26−/− mice displayed short latencies to nociceptive stimuli (hot plate test: 6.6 ± 1.2 s versus 8.6 ± 1.5 s, P < 10 −4; tail pinch test: 3.1 ± 0.6 s versus 4.2 ± 0.8 s, P < 10 −3). Administration of an SP (NK1) receptor antagonist or DPP-IV to CD26−/− mice normalised latencies. DPP-IV inhibitors decreased latencies only in CD26+/+ mice. Conclusions Our observations represent the first fundamental evidence showing that DPP-IV influences pain perception via modulation of the peripheral SP concentration. Our work also highlights the role of peripheral NK1 receptors in nociception.

The Effect of Sunscreen on Skin Elastase Activity Induced by Ultraviolet-A Irradiation

It has been reported that application of sunscreens prevents the photoaging of skin in animal models and in humans. We irradiated the dorsal skin of hairless mice with ultraviolet-A (UVA), and investigated the effects of sunscreens on skin elastase activity and on skin properties. Six-week-old female HR/ICR hairless mice were used in these experiments. After being treated with either a UVA sunscreen (also containing ultraviolet-B (UVB) sunscreen to eliminate any slight UVB in the UVA lamps; Protection Factor of UVA (PFA)=6, Sun Protection Factor (SPF)=20) or a vehicle, the dorsal skins of mice were irradiated with the UVA lamps at 22.3 J/cm(2)/d, 5 times a week. At the end of 15 weeks skin properties were evaluated and elastase activities were measured. In the vehicle control group, UVA irradiation increased the brightness and yellowing of the skin, decreased the water content of the stratum corneum, increased skin thickness, decreased skin elasticity, increased skin elastase activity, and decreased the ability of the skin to recover in a pinch test, as compared to an unirradiated group. All these differences were statistically significant. In the UVA sunscreen group, both the UVA induced skin damage and the increase in skin elastase activity were significantly inhibited, as compared to the vehicle group. However, as compared to the unirradiated group, skin elastase activity was significantly increased and immediate extensibility of skin (Ue) was significantly decreased, thereby indicating that the UVA sunscreen did not prevent photoaging to the same level as the unirradiated group. These results suggest the partial efficacy of the topical photoprotection from UVA by the sunscreen in inhibiting elastase activation, and also suggest the possibility of reducing photoaging.

Evaluation of Donor Site Function and Morbidity of the Fasciocutaneous Radial Forearm Flap

To assess the results of the use of the free radial forearm flap in terms of objective morbidity and subjective patient response. The donor sites were examined from 37 patients who underwent reconstruction with a free fasciocutaneous radial forearm flap in the head and neck after ablative tumor surgery. Patients were asked to fill in a written questionnaire. The following additional tests were performed: resting skin temperature of digits I and V, temperature after submersion in iced water, grip and pinch tests, and goniometry. Resting skin temperature was slightly decreased for donor hands 0.69 degrees C (P < .001) and 0.31 degrees C (P = .048) for digits I and V, respectively, but recovery after submersion in iced water showed no differences. The strength tests and goniometry revealed no statistically significant findings between donor and control sides. On the questionnaire, 9 patients (24%) reported slightly impaired function, 14 (38%) could not wear their watch or bracelet, 17 (46%) reported numbness, 5 (14%) reported soreness, 5 (14%) reported itching, 6 (16%) reported cold intolerance, 5 (14%) reported bad cosmetic appearance, and 9 (24%) expressed the opinion that they were insufficiently counseled. There is a negligible objective morbidity of a free radial forearm flap harvest procedure, but a number of patients have subjective complaints when asked. Elaborate presurgical counseling can probably reduce these complaints.

Small conductance calcium-activated K+ channels, SkCa, but not voltage-gated K+ (Kv) channels, are implicated in the antinociception induced by CGS21680, a A2A adenosine receptor agonist

It has been shown that A2A adenosine receptors are implicated in pain modulation. The precise mechanism by which activation of A2A receptors produces analgesic effects, however, remains unclear. The aim of this study was to investigate the possible involvement of apamin-sensitive calcium-activated potassium channels (SKCa) and voltage-gated potassium (Kv) channels in A2A receptor activation-induced analgesic effects. Using mice, we evaluated the influence of apamin, a non specific blocker of SKCa channels, Lei-Dab7 (an analog of scorpion Leiurotoxin), a selective blocker of SKCa2 channels, and kaliotoxin (KTX) a Kv channel blocker, on the CGS 21680 (A2A adenosine receptor agonist)-induced increases in hot plate and tail pinch latencies. All drugs were injected in mice via the intracerebroventricular route. We found that apamin and Lei-Dab7, but not KTX, reduced antinociception produced by CGS21680 on the hot plate and tail pinch tests in a dose dependent manner. Lei-Dab 7 was more potent than apamin in this regard. We conclude that SKCa but not Kv channels are implicated in CGS 21680-induced antinociception.

Endoscopic carpal tunnel release using a new median nerve protector.

We designed a reusable median nerve protector for endoscopic carpal tunnel release (ECTR) and prospectively evaluated its safety and efficacy. Therapeutic study--Investigating the results of treatment. Seventy-two patients (97 palms) with carpal tunnel syndrome were operated on endoscopically with the new median nerve protector. Patients were followed-up at 1, 3, 6, 12, and 24 weeks postoperatively. Evaluation included the symptom severity scale, functional status scale, wound pain and scar tenderness, monofilament sensory mapping, grip strength measurement, and pin strength gauge. No patients sustained iatrogenic neurovascular injury or hematoma, but 3 developed superficial wound infections postoperatively. The symptom severity score decreased from 3.8 points preoperatively to 2.3 at 1 week, 1.9 at 3 weeks, and 1.3 at 6 weeks, and remained at 1 point at 12 and 24 weeks postoperatively. The functional status score dropped from 3.8 points to 2.8 at 1 week, 2 at 3 weeks, 1.5 at 6 weeks, and 1 at 12 weeks and thereafter. Semmes Weinstein monofilament mapping improved in all operated hands (59) of the 44 patients not lost to follow-up by 24 weeks. Tip pinch testing and grip strength showed gradual improvement as early as 3 weeks postoperatively. The mean value of the postoperative scar tenderness score dropped from 2.4 points at 1 week to 1.7 points at 3 weeks, 1.3 at 6 weeks, 1.2 at 12 weeks, and 1 point after 12 weeks. This new median nerve protector provides clear visualization of neurovascular structures and is a safe and reliable tool for single-portal ECTR. Level IV.

Sex-related differences in the regeneration of sensory axons and recovery of nociception after peripheral nerve crush in the rat

Sex-related differences regarding the regeneration of nociceptive axons and the recovery of nociception after sural nerve crush injury were examined in rats. The elongation rate of the fastest regenerating sensory axons in females started to increase after the first 6 days. This resulted in about 15% greater axon elongation distance at 8 days after crush in female than in male rats as determined by the nerve pinch test. The number of regenerating sensory axons in female and male rats, however, was not different. The recovery of nociception in the instep started earlier and was more extensive in females than in males during the entire 24-week recovery period, so that the pain sensitive area was finally about 20% larger in females than in males. Although ovariectomy significantly reduced plasma estradiol concentration in female rats, it did not change the elongation distance of regenerating nociceptive axons, which remained significantly greater than in male rats. Elimination of the cells in the distal nerve segment by freezing revealed that a more effective cell support in the distal nerve segment is probably responsible for faster regeneration of nociceptive axons in females than in males, rather than the circulating female sex hormones.

Long-term effects of pubertal anabolic–androgenic steroid exposure on reproductive and aggressive behaviors in male rats

The current study examined acute and long-term effects of anabolic–androgenic steroid (AAS) exposure during puberty on copulation, vocalizations, scent marking, and intermale aggression, both with and without tail pinch, in intact male rats. Animals received 5 mg/kg of testosterone, nandrolone, stanozolol, or vehicle, beginning at puberty. After 5 weeks, behavior tests were performed while continuing AAS injections. AAS treatment was then discontinued. Behaviors were tested during 3–5 weeks, 9–11 weeks, and 15–17 weeks of withdrawal. During AAS administration, stanozolol males showed significant reductions in all behaviors compared with controls, except aggression with tail pinch. Nandrolone treatment significantly reduced vocalizations and scent marking, and testosterone had no significant effect on behavior. During withdrawal, behaviors in stanozolol males recovered to control levels at variable rates: aggression at 4 weeks; mounts, vocalizations, and scent marking at 9 weeks; and ejaculations at 15 weeks of withdrawal. Stanozolol males showed significantly higher levels of tail pinch-induced aggression during every withdrawal test. Nandrolone-treated males scent-marked at control levels by 9 weeks withdrawal but displayed significantly fewer vocalizations and significantly more tail pinch-induced aggression than controls for the entire study. Testosterone-treated males scent-marked significantly below controls at 3 weeks withdrawal and showed significantly more tail pinch-induced aggression at 5 weeks withdrawal. All three AAS significantly increased tail pinch-induced aggression compared with corresponding nontail pinch tests, even at study endpoint. These results suggest that alterations in androgen-dependent behaviors by pubertal AAS exposure can persist long after drug exposure, and some effects may even be permanent.

Inhibition of p38 MAP kinase activity enhances axonal regeneration

Tumor necrosis factor alpha (TNF)-induced cellular signaling through the p38 mitogen-activated protein kinase (p38 MAPK) pathway plays a critical role in Wallerian degeneration and subsequent regeneration, processes that depend on Schwann cell (SC) activity. TNF dose-dependently induces Schwann cell and macrophage activation in vivo and apoptosis in primary SC cultures in vitro, while inhibition of p38 MAPK is thought to block these cellular processes. We show with Western blots that after sciatic nerve crush injury, phosphorylated p38 (p-p38) MAPK is significantly increased ( P < 0.01) in distal nerve segments. In tissue sections, p38 co-localized immunohistochemically with activated Schwann cells (GFAP) and to a lesser degree with macrophages (ED-1). In other experiments, animals were gavaged with Scios SD-169 (10 or 30 mg/kg) or excipient (PEG300) 1 day before and daily after crush injury to the sciatic nerve. SD-169 is a proprietary oral inhibitor of p38 MAPK activity. The rate of axonal regeneration was determined by the functional pinch test and was significantly increased in treated animals 8 days after crush injury ( P < 0.05; 30 mg/kg dose). In SD-169-treated animals with nerve transection, nerve fibers regenerating through a silicone chamber were morphologically more mature than untreated nerves when observed 28 days after transection. TNF immunofluorescence of distal nerve segments after crush injury suggested that SD-169 reduced SC TNF protein. In support of these findings, SD-169 significantly reduced ( P < 0.05) TNF-mediated primary SC death in culture experiments. We conclude that inhibition of p38 activity promotes axonal regeneration through interactions with SC signaling and TNF activity.

A comparison of static and dynamic wrist splints using electromyography in individuals with rheumatoid arthritis

This study compared strength, dexterity, and the muscle activation of individuals with rheumatoid arthritis (RA) when different splints were worn. Five persons with RA were observed in four splint conditions (none, static, hinged, spiral) during grip, pinch, and dexterity tests by recording muscle activity of eight muscles in the upper extremity using electromyography (EMG). Statistically significant differences were found in clinical tests when hinged (p<0.001) and spiral splints (p = 0.02) were worn. Grip strength decreased when hinged splints were worn, whereas two-point pinch increased and dexterity improved on the Nine-Hole Peg Test with the spiral splint. Although no significant EMG differences were found during different splint conditions, wrist muscles were recruited more for grip, and shoulder muscles were used most during pinch and dexterity tests. Individuals with RA who wore splints had decreased grip when wearing hinged splints, but improved pinch and dexterity were found when the spiral splint was worn. Increased use of proximal shoulder muscles was observed during pinch and dexterity tests with and without splints.

Sex-related difference in collateral sprouting of nociceptive axons after peripheral nerve injury in the rat

Possible sex-related differences in the extent of collateral sprouting of noninjured nociceptive axons after peripheral nerve injury were examined. In the first experiment, peroneal, tibial, and saphenous nerves were transected and ligated in female and male rats. Eight weeks after nerve injury, skin pinch tests revealed that the nociceptive area of the noninjured sural nerve in the instep skin expanded faster in females; the final result was a 30% larger increase in females than in males. In the second experiment, the end-to-side nerve anastomosis was used as a model for axon sprouting. In addition to the previous procedure, the end of an excised peroneal nerve segment was sutured to the side of the intact sural nerve. Eight weeks later, collateral sprouting of nociceptive axons into the anastomosed peroneal nerve segment was assessed by the nerve pinch test and axon counting. There was no significant difference with respect to the percentages of male and female rats with a positive nerve pinch test. The number of myelinated axons in the anastomosed nerve segment was significantly larger in female (456 ± 217) than in male (202 ± 150) rats, but the numbers of unmyelinated axons were not significantly different. In normal sural nerves, the numbers of either all myelinated axons or thin myelinated axons did not significantly differ between the two sexes. Therefore, the more extensive collateral axon sprouting observed in female than in male rats is probably due to the higher sprouting capacity of thin myelinated sensory axons in females.

Role of metallothioneins in peripheral nerve function and regeneration.

The physiological role of the metallothionein (MT) family of proteins during peripheral nerve injury and regeneration was examined in Mt1+ 2 and Mt3 knockout (KO) mice. To this end, the right sciatic nerve was crushed, and the regeneration distance was evaluated by the pinch test 2-7 days postlesion (dpl) and electrophysiologically at 14 dpl. The quality of the regeneration was assessed by light microscopy and immunohistochemical methods. The results show that the regeneration distance was greater in the Mt3 KO than in the Mt1+ 2 KO mice, whereas control mice showed intermediate values. Moreover, the number of regenerating axons in the distal tibial nerve was significantly higher in Mt3KO mice than in the other two strains at 14 dpl. Immunoreactive profiles to protein gene product 9.5 were present in the epidermis and the sweat glands of the plantar skin of the hindpaw of the Mt3 KO group. The improved regeneration observed with the Mt3 KO mice was confirmed by compound nerve action potentials that were recorded from digital nerves at 14 dpl only in this group. We conclude that Mt3 normally inhibits peripheral nerve regeneration.

Activation of spinal histamine H 3 receptors inhibits mechanical nociception

Previous studies have suggested a possible pain-modulatory role for histamine H 3 receptors, but the localization of these receptors and nature of this modulation is not clear. In order to explore the role of spinal histamine H 3 receptors in the inhibition of nociception, the effects of systemically (subcutaneous, s.c.) and intrathecally (i.t.) administered histamine H 3 receptor agonists were studied in rats and mice. Immepip (5 mg/kg, s.c.) produced robust antinociception in rats on a mechanical (tail pinch) test but did not alter nociceptive responses on a thermal (tail flick) test. In contrast, this treatment in mice (immepip, 5 and 30 mg/kg, s.c.) did not change either mechanically or thermally evoked nociceptive responses. When administered directly into the spinal subarachnoid space, immepip (15–50 μg, i.t.) and R-α-methylhistamine (50 μg, i.t.) had no effect in rats on the tail flick and hot plate tests, but produced a dose- and time-dependent inhibition (90–100%) of nociceptive responses on the tail pinch test. This attenuation was blocked by administration of thioperamide (10 mg/kg, s.c.), a histamine H 3 receptor antagonist. Intrathecally administered thioperamide also reversed antinociceptive responses induced by systemically administered immepip, which demonstrates a spinal site of action for the histamine H 3 receptor agonist. In addition, intrathecally administered immepip (25 μg) produced maximal antinociception on the tail pinch test in wild type, but not in histamine H 3 receptor knockout (H 3KO) mice. These findings demonstrate an antinociceptive role for spinal histamine H 3 receptors. Further studies are needed to confirm the existence of modality-specific (i.e. mechanical vs. thermal) inhibition of nociception by these receptors, and to assess the efficacy of spinally delivered histamine H 3 receptor agonists for the treatment for pain.

The pinch test: a simple technique for determining the pressure of an endotracheal tube cuff

The pinch test: a simple technique for determining the pressure of an endotracheal tube cuff

Changes in bladder neck geometry and closure pressure after midurethral anchoring suggest a musculoelastic mechanism activates closure.

The aim of this study was to investigate the anatomical origins and clinical significance of cough pressure transmission ratio (CTR) by using virtual-operation (VO) techniques. Thirty-four patients underwent perineal ultrasound examination, standard urethral pressure cough testing both with and without unilateral midurethral anchoring (VO), all tests being performed without urethral elevation. In eight patients where there was no change in CTR, a one-sided fold of suburethral vagina (VO) was taken (pinch test) and the CTR repeated. After midurethral anchoring, maximal urethral pressure increased from a mean of 33.25 cm H2O to a mean of 58.06 cm H2O (P < 0.0001) and restoration of anatomy was noted in all 11 patients who had obvious funneling on straining. Conversion of a <100% CTR to >100% CTR in the proximal urethra was observed in 14 of 22 patients (P < 0.005), with no significant change noted in the distal urethra. Further conversion of CTR was noted in six of the remaining eight patients with unilateral plication of suburethral vagina (pinch test). A musculoelastic closure mechanism most likely activates urethral closure. CTR is most likely an index of changed intraurethral area, not necessarily closure, and may be a more sensitive objective test than perineal ultrasound for diagnosing urethral narrowing, especially when used with virtual-operation techniques.

A COMPARISON OF PERIPHERAL NERVE REGENERATION IN ACELLULAR MUSCLE AND NERVE AUTOGRAFTS

Regeneration of the rat sciatic nerve through acellular muscle and nerve autografts was evaluated 6-28 days postoperatively by the sensory pinch test, immunocytochemical staining for neurofilaments, and light and electron microscopy. Data points generated by the pinch test were plotted against postoperative time periods and by the use of regression analysis the initial delay period for muscle grafts was determined to 10.3 days. This value was similar to that previously published for acellular nerve grafts (9.5 days), but significantly longer than that for fresh nerve grafts (3.6 days). The calculated regeneration rate (slope of the regression line) for muscle grafts (1.8 mm/day) did not differ significantly (p > 0.05) from that calculated for acellular nerve grafts (2.1 mm/day) or for fresh nerve grafts (1.5 mm/day). The front of regenerating axons shown by axonal neurofilament staining confirmed the pinch test results. Both types of acellular grafts were repopulated with host non-neuronal cells and the muscle graft contained occasional ectopic muscle fibres. Remnants of graft basal laminae were evident at the ultrastructural level. These results indicate the suitability of either acellular muscle or nerve grafts for nerve repair despite their prolonged initial delay periods compared with conventional fresh nerve grafts.

The effect of hyperbaric oxygen treatment on early regeneration of sensory axons after nerve crush in the rat.

Abstract The effect of hyperbaric oxygen treatment (HBO) on sensory axon regeneration was examined in the rat. The sciatic nerve was crushed in both legs. In addition, the distal stump of the sural nerve on one side was made acellular and its blood perfusion was compromised by freezing and thawing. Two experimental groups received hyperbaric exposures (2.5 ATA) to either compressed air (pO2 = 0.5 ATA) or 100% oxygen (pO2 = 2.5 ATA) 90 minutes per day for 6 days. Sensory axon regeneration in the sural nerve was thereafter assessed by the nerve pinch test and immunohistochemical reaction to neurofilament. HBO treatment increased the distances reached by the fastest regenerating sensory axons by about 15% in the distal nerve segments with preserved and with compromised blood perfusion. There was no significant difference between the rats treated with different oxygen tensions. The total number of regenerated axons in the distal sural nerve segments after a simple crush injury was not affected, whereas in the nerve segments with compromised blood perfusion treated by the higher pO2, the axon number was about 30% lower than that in the control group. It is concluded that the beneficial effect of HBO on sensory axon regeneration is not dose-dependent between 0.5 and 2.5 ATA pO2. Although the exposure to 2.5 ATA of pO2 moderately enhanced early regeneration of the fastest sensory axons, it decreased the number of regenerating axons in the injured nerves with compromised blood perfusion of the distal nerve stump.